• verify local cert
  • s_client
    • with cert debug
  • curl
  • openssl
    • get crt information
    • get csr information
  • java ssl
    • InstallCert.java
• verify remote cert
  • openssl & s_client
    • verify certs
  • curl
  • keytool
  • nmap

verify local cert

s_client

$ openssl s_client -state -msg -connect domain.sample.com:443

with cert debug

$ openssl s_client -state \
                   -debug \
                   -connect domain.sample.com:443 \
                   -cert domain.sample.com-server.crt \
                   -key domain.sample.com-server.key \

curl

$ curl -vvv \
       [--cacert server.crt \]
       https://domain.sample.com:443/artifactory

• or

  $ curl -vvv \
         -i \
         -L \
         [--cacert server.crt \] \
         https://domain.sample.com:443/artifactory
  

openssl

get crt information

• ca.crt

  $ openssl verify ca.crt
  

  • or

    $ openssl x509 -noout -text -in ca.crt
    

• server.crt

  $ openssl x509 -inform PEM \
                 -in server.crt \
                 -text \
                 -out certdata.pem
  

get csr information

$ openssl req -noout -text -in server.csr

java ssl

// SSLPoke.java
import javax.net.ssl.SSLParameters;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
import java.io.*;

/** Establish a SSL connection to a host and port, writes a byte and
 * prints the response. See
 * http://confluence.atlassian.com/display/JIRA/Connecting+to+SSL+services
 */
public class SSLPoke {
  public static void main(String[] args) {
    if (args.length != 2) {
      System.out.println("Usage: "+SSLPoke.class.getName()+" <host> <port>");
      System.exit(1);
    }
    try {
      SSLSocketFactory sslsocketfactory = (SSLSocketFactory) SSLSocketFactory.getDefault();
      SSLSocket sslsocket = (SSLSocket) sslsocketfactory.createSocket(args[0], Integer.parseInt(args[1]));

      SSLParameters sslparams = new SSLParameters();
      sslparams.setEndpointIdentificationAlgorithm("HTTPS");
      sslsocket.setSSLParameters(sslparams);

      InputStream in = sslsocket.getInputStream();
      OutputStream out = sslsocket.getOutputStream();

      // Write a test byte to get a reaction :)
      out.write(1);

      while (in.available() > 0) {
        System.out.print(in.read());
      }
      System.out.println("Successfully connected");

    } catch (Exception exception) {
        exception.printStackTrace();
        System.exit(1);
    }
  }
}

• extract cert from server:

  $ openssl s_client -connect server:443
  

• negative test cert/keytool:

  $ java SSLPoke server 443
  

  • you should get something like

    javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
    

• import cert into default keytool:

  $ keytool -import -alias alias.server.com -keystore $JAVA_HOME/jre/lib/security/cacerts
  

• positive test cert / keytool:

  java SSLPoke server 443
  
  // you should get this:
  // Successfully connected
  

• import certificate into your local TrustStore

  -Djavax.net.ssl.trustStore will override the default truststore (cacerts). copy the default one and then add cert and set it via -Djavax.net.ssl.trustStore so default CA won't be lost.

  $ keytool -import \
            -trustcacerts \
            -storepass changeit \
            -file "./class 1 root ca.cer" \
            -alias C1_ROOT_CA \
            -keystore ./LocalTrustStore
  
  # use it in JAVA:
  $ java -Djavax.net.ssl.trustStore=./LocalTrustStore -jar SSLPoke.jar $HOST $PORT
  

• list expired date for all in cacerts

  $ keytool --list -v --keystore cacerts | grep "until:" | sed 's/^.*until: //'
  

InstallCert.java

reference:

• unable to find valid certification path to requested target

compile first

$ javac InstallCert.java

• Access server, and retrieve certificate (accept default certificate 1)

  $ java InstallCert [host]:[port]
  

• Extract certificate from created jssecacerts keystore

  $ keytool -exportcert -alias [host]-1 -keystore jssecacerts -storepass changeit -file [host].cer
  

• Import certificate into system keystore

  $ keytool -importcert -alias [host] -keystore [path to system keystore] -storepass changeit -file [host].cer
  

verify remote cert

openssl & s_client

$ openssl s_client -showcerts -connect www.domain.com:443

• or

  $ openssl s_client -showcerts \
                     -starttls imap \
                     -connect www.domain.com:443
  CONNECTED(00000005)
  

• or using local client cert for debug purpose

  $ openssl s_client -showcerts \
                     -cert cert.cer \
                     -key cert.key \
                     -connect www.domain.com:443
  

• or

   $ openssl s_client -connect www.domain.com:443 |
     openssl x509 -text -noout |
     grep -A 1 -i key
  

• or use specify acceptable ciphers for ssl handshake

  $ openssl s_client -showcerts \
                     -cipher DHE-RSA-AES256-SHA \
                     -connect www.domain.com:443
  

• or get enddate only

  $ echo | openssl s_client \
                   -connect www.domain.com:443 2>/dev/null |
           openssl x509 -noout -enddate
  notAfter=Nov 28 23:59:59 2020 GMT
  

verify certs

$ echo | openssl s_client -showcerts \
                          -servername www.domain.com \
                          -connect www.domain.com:443 2>/dev/null |
         openssl x509 -inform pem -noout -text

• get ssl only

  $ echo | openssl s_client -showcerts \
                            -connect www.domain.com:443 2>/dev/null |
                            sed -n '/BEGIN.*-/,/END.*-/p'
  

curl

$ curl -vvI https://www.domain.com

• print ssl only

  $ curl --insecure \
         -vvI https://www.domain.com 2>&1 |
    awk 'BEGIN { cert=0 } /^\* SSL connection/ { cert=1 } /^\*/ { if (cert) print }'
  

keytool

$ keytool -printcert -sslserver www.domain.com:443

nmap

$ nmap -p 443 --script ssl-cert www.domain.com [-v]